The main objective of this research project is to understand the role of mitochondrial RNA polymerase in extranuclear transcription, and its possible relationship to prokaryotic RNA polymerase. Past attempts to obtain sufficient quantity of mitochondrial RNA polymerase from the hepatoma appears to be due to leakage of the enzyme into the cytosol fraction during initial homogenization of the tissue in isotonic aqueous buffers. An enzyme activity peak, resolved by DEAE-Sephadex column chromatography of the cytosol fraction, resembles mitochondrial RNA polymerase with respect to its size and metal ion requirements. Since the level of this enzyme is several times greater than that of the enzyme normally present in the isolated mitochondria (which might be the tightly bound enzyme population), a substantial quantity of the enzyme can be obtained from 100-200 g of tissue. This enzyme will be purified extensively and its properties compared with those of the corresponding liver enzyme. The nature of the product using mitochondrial DNA, number of initiation sites on this template and frequency of initiation will be determined using the polymerase from liver and tumor. These studies may provide information as to the role of the mitochondrial RNA polymerase in extranuclear transcription, and may also provide a mechanism (at the level of transcription) for reduced levels of several mitochondrial proteins in hepatomas.